1. Field of the Invention
The present invention broadly relates to a keyboard for use with a programmable, i.e., microprocessor-based, terminal and, more particularly, is concerned with the incorporation of a cycle timer controller in the keyboard for making every key switch on the keyboard cyclable and thereby provide a universal or general-purpose keyboard useable with any programmable terminal.
2. Description of the Prior Art
Character cycling during the performance of keystroking operations on a terminal keyboard is an essential tool for efficient use of the terminal and, therefore, is provided in virtually all terminals on the market today. Some examples of its use are to move the cursor across the terminal display screen, underline data and to delete characters of data in a particular line. All of these steps can be accomplished quickly and with a negligible expenditure of effort through character cycling.
Prior art keyboard design practices for providing character cycling capability have basically taken two approaches. First, the keyboard is provided with a separate "cycle" key switch that has to be depressed along with the particular other key switch which the operator intends to cycle. Second, a specific keyboard is designed to make certain of the key switches cyclable. Also, the rate at which the character is cycled upon depression of a particular one of the cyclable key switches is controlled by the keyboard. Thus, each time one desires a different selection of cyclable key switches and a different cycle rate on a keyboard for some other terminal, the keyboard has to be redesigned.
The disadvantages underlying both of these prior art approaches are readily apparent. With respect to the first approach, the necessity of having to depress two key switches at the same time and hold them both down in order to cycle the character of one is particularly inconvenient and distracting for the terminal operator. On the other hand, with the second approach the need to redesign the keyboard in order to provide for a different selection of cyclable key switches with a different cycle rate is wasteful in terms of the design and production time required to make and implement the redesign.